My Mruder (bruder cat320 something look alike)

[cdm]

This will be a quick and disorganized run down since i have about 400 things on the honey do list for today alone.. hard to find me time lately.

This is a pooper scooper. Its job is to go in the reptile cage and turn over the soil. Not as hardcore as digging a basement ( i love that thread!), but it allows me to get away with building it less than milspec tough. Besides its all red clay out where i live; you aren't digging through that regardless.

At first i thought about simply converting the bruder cat but the thing is a joke and so I opted to make a lot of my own parts, just using the body canopy at the end. I thought about extending this as well to make it into a 40 or 60ton but I dont want another super long project to drag on. So it will stay as a 20 ton with a custom long reach arm, which is what i really need.

Initially i extended the lower arm on the stock cat, but it was still too small and the geometry was wrong as far as cyllinder and bucket control angles. So i machined one out of reinforced plastic stock. Drilled and tapped with 6mm sleeves and the shafts are 3mm hardened ss stock.

There are 2 of those holding the bucket itself, the epoxy is there to help keep it all centered as i mounted it and what not. most if not all of that will be cut away. The range of motion is phenomenal with the 172mm cylinder and the longer than scale bucket oscilting links.

To give you a size idea of mine vs the stock lower arm:



The long arm is custom extended bruder one (3 extensions to get the proper geometry). I could cut that too out of plastic stock but i already invested a lot in the stock extension. Pics of that later when im done prettying it up. I still might cut one, depending on how much power i get out of the system - that solid plastic is heavy!

Quick test of the tracks section. This is weighted with lead (epoxy is a good bonding agent for that, again that will be machined away, prettied up and painted and hidden with top attached) and it weighs as it stands at close to 5lbs. I can make it 10lbs easy if i ballast it all. So there is room to play with that if COG is off down the road. Right now i left it as is since i have a few lbs in the top floor ballast. Also there will be a battery in the lower body for the turn table motor (it gets it's own battery yes - fewer wires to run between the 2 sections this way)

The servos are factory modified robotic servo motors producing over 100oz of torque each at 6v. This test is with an almost dead 4.8v pack and the throttle didn't go over 20% even here. Of course, friction on the floor was pretty slim so im quite i'll use all of the 200+oz down the road. If i really wanted to i could have made it a quad sprocket for over 400oz of power, but that's an overkill.. Could have also gone with direct motor drive (have them here) but i just WANTED to play with these awesome servo blocks. As you can see quite easy to mount and adjust height and position to get the perfect mesh with track and ground level. The tracks have also been extended a few links over stock. Width is the same; see comments above about making the body scale bigger.


I have the base plate, the turntable main floor - all that ready -1/8 and 1/4 t6 alum plate that was interesting cutting to shape. Waiting for some hardware to attach the bottom floor to the main beams. Then it's time to tinker with the hydraulics. I decided to stay brushed for now, using a cool new motor over the stock 540 can. It's shorter to boot.

The drive section will not be as scale as other's but this isn't a conversion per say. I will opt for function over realism any day when it comes to something like that. I will probably lose the H pattern the tracks section has but it's ok.


http://www.youtube.com/watch?v=0fB9vQ8YkWk